The present invention relates to a liquid crystal display device, and in particular to a technology useful for application to a backlight of a liquid crystal display device.
Widely used as display sections of portable equipment such as mobile phones are TFT (Thin Film Transistor) type liquid crystal display modules each provided with a small-sized color liquid crystal panel having subpixels in the order of 240×320×3 in number.
FIG. 16A is a schematic exploded perspective view illustrating a rough configuration of a conventional liquid crystal display module. As shown in FIG. 16A, in the conventional liquid crystal display module, arranged in the order shown in FIG. 16A within a metal frame 16, for example, a die cast frame made of magnesium alloy, are a liquid crystal display panel LCD, a mold 11 formed of synthetic resin, for example, and a light reflective sheet 12. Disposed within the mold 11 are a light guide 10, a group of optical sheets (upper and lower light diffusing sheets and a lens sheet) 15, and a light source (white light emitting diodes) 13.
The liquid crystal display panel LCD is fabricated by attaching together a glass substrate TFTSUB provided with thin film transistors, drain lines, gate lines and others (not shown) and a glass substrate CFSUB provided with a counter electrode, color filters and others (not shown) with a sealing agent (not shown) interposed therebetween, then filling a liquid crystal material (not shown) into a space between the two glass substrates TFTSUB, CFSUB, and sealing off the space, and then attaching polarizing sheets POL1 and PLO2 on the outer surfaces of the two glass substrates TFTSUB and CFSUB, respectively. In FIG. 16A, reference character DRV denote semiconductor chips for driving the subpixels of the liquid crystal display panel LCD
The frame 16 in FIG. 16A is required to be electro-conductive so as to prevent EMI (Electromagnetic Interference) and mechanically strong, and therefore the frame 16 is formed of a magnesium alloy die cast, for example.
FIG. 16B is a cross-sectional view of the conventional liquid crystal display module of FIG. 16A in the assembled condition taken along line XVIB-XVIB of FIG. 16A. The liquid crystal display panel LCD is attached to a recess formed in the mold 11 by using double-faced adhesive tapes 100.
FIGS. 17A and 17B are illustrations for explaining the mold 11 shown in FIGS. 16A and 16B, FIG. 17A is a plan view of the mold 11, and FIG. 17B is a cross-sectional view of the mold 11 taken along line XVIIB-XVIIB of FIG. 17A. As shown in FIGS. 17A and 17B, the mold 11 shown in FIG. 16A is of the shape of a frame (or a cylinder) having a rectangular cross section, and is formed with engaging portions 1a. 
FIGS. 18A-18C are illustrations for explaining the frame 16 shown in FIGS. 16A and 16B, FIG. 18A is a plan view of the frame 16, and FIG. 18B is a cross-sectional view of the frame 16 taken along line XVIIIB-XVIIIB of FIG. 18A, FIG. 18C is an enlarged view of an encircled portion A of FIG. 18B, and FIG. 18D is an enlarged perspective view of the encircled portion A of FIG. 18B. As shown in FIGS. 18A-18D, the frame 16 has a bottom portion 30 and a sidewall 31 formed along the peripheries of the bottom portion 30, and the frame 16 has through holes 1b therein extending continuously from the bottom portion 30 to the sidewall 31.
FIGS. 19A-19C are illustrations for explaining a method of fixing together the mold 11 and the frame 16 shown in FIG. 16A, FIG. 19A is a plan view of an assembly of the mold 11 and the frame 16, FIG. 19B is a cross-sectional view of the assembly of FIG. 19A taken along line XIXB-XIXB of FIG. 19A, and FIG. 19C is an enlarged view of an encircled portion B of FIG. 19B. Incidentally, the liquid crystal display panel LCD, the light guide 10, the group of optical sheets 15 or the light source 13 are not shown in FIGS. 19A-19C for the sake of simplicity.
As shown in FIGS. 19A-19C, the mold 11 is fixed to the frame 16 by inserting the engaging portions 1a formed in the sidewall of the mold 11 into the through holes 1b formed in the frame 16, and engaging tips of the engaging portions 1a with the sidewall of the frame 16 (or hooking the tips of the engaging portions 1a to the sidewall of the frame 16).
Incidentally, the shapes of the mold 11 and the frame 16 are schematically illustrated in FIGS. 16A-19C and later-explained figures for explaining the features of the present invention clearly, and therefore they do not always represent the shapes of the mold 11 and the frame 16 in practical applications.